National Center for Advancing and Translational Sciences Genetic and Rare Diseases Information Center, a program of the National Center for Advancing and Translational Sciences

Idiopathic hypersomnia


Other Names:
Idiopathic hypersomnolence; Primary hypersomnia
Idiopathic hypersomnia (IH) is a neurological sleep disorder that can affect many aspects of a person's life. Symptoms often begin between adolescence and young adulthood and develop over weeks to months. People with IH have a hard time staying awake and alert during the day (chronic excessive daytime sleepiness, or EDS). They may fall asleep unintentionally or at inappropriate times, interfering with daily functioning. They may also have difficulty waking up from nighttime sleep or daytime naps. Sleeping longer at night does not appear to improve daytime sleepiness.[1] IH is a chronic disorder. Symptoms may remain generally stable over time, or severity may fluctuate over time.[1][2]

The cause of IH is not known. Some people with IH have other family members with a sleep disorder such as IH or narcolepsy.[1] Currently there is no treatment approved by the FDA specifically for IH, but some people may be helped by medications used to treat other disorders ("off-label") such as narcolepsy.[1][3] Unlike in narcolepsy, in which scheduled naps may help, daytime naps in people with IH are often long yet unrefreshing.[1][4] People with IH may experience improvement with medication; however, medications do not work well for all people or may stop working over time.[1][3]
Last updated: 6/13/2018
Common symptoms of idiopathic hypersominia (IH) include:[5][6][2]
  • Chronic excessive daytime sleepiness (EDS): sleepiness during the day that makes it difficult to perform normal daily activities, including both work- and social-related activities.
  • Sleeping 9 hours or more over 24-hour periods, yet not feeling refreshed upon waking from nighttime sleep or naps.
  • Non-refreshing daytime napping.
  • Sleep drunkeness after nighttime sleep and naps: difficulty waking up and feeling an uncontrollable desire to go back to sleep.
  • "Brain fog" while awake: experiencing problems with memory, attention and concentration.
  • Headaches.
Other symptoms reported by people with IH include:[5][6][2]
Last updated: 6/13/2018

This table lists symptoms that people with this disease may have. For most diseases, symptoms will vary from person to person. People with the same disease may not have all the symptoms listed. This information comes from a database called the Human Phenotype Ontology (HPO) . The HPO collects information on symptoms that have been described in medical resources. The HPO is updated regularly. Use the HPO ID to access more in-depth information about a symptom.

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Medical Terms Other Names
Learn More:
HPO ID
80%-99% of people have these symptoms
Excessive daytime somnolence
More than typical sleepiness during day
0001262
Hypersomnia
Excessive sleepiness
0100786
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Last updated: 7/1/2020
Treatments for hypersomnia are generally aimed at excessive daytime sleepiness (EDS), rather than at sleep duration or sleep drunkenness (confusion upon waking up). Although there are multiple treatments approved by the Food and Drug Administration (FDA) for narcolepsy, there are no FDA-approved treatments idiopathic hypersomnia (IH). Therefore, treatment generally involves off-label use of medications approved for narcolepsy. Unfortunately, the use of these medications is inadequate to improve symptoms in many people with IH. These medication options may include:[7]

There are also several emerging therapies for cases that do not respond to the above types of medications. These include sodium oxybate, clarithromycin, and flumazenil.[7]

Non-medical approaches such as behavior modification are not generally effective for people with IH. Unlike in narcolepsy, where scheduled naps can help, daytime naps in people with IH are typically long and nonrestorative.[1]

People with IH should avoid activities that may be dangerous, and should avoid driving or operating dangerous machinery unless sleepiness is well controlled by medication.[1]

Following up with physicians at least annually (preferably more frequently) is recommended to assess for side effects of medication, sleep or mood disturbances, adequate control of symptoms, and any work-related or social issues.[1]
Last updated: 6/1/2017

Related diseases are conditions that have similar signs and symptoms. A health care provider may consider these conditions in the table below when making a diagnosis. Please note that the table may not include all the possible conditions related to this disease.

Conditions with similar signs and symptoms from Orphanet
Clinical examination (based more or less on a sleep diary or on actimetry) eliminates chronic insufficient sleep syndrome. Sleep recordings exclude narcolepsy, rhythm disorders or fragmented night sleep due to motor or respiratory events. A psychological examination excludes hypersomnia of psychiatric origin. Finally, neuro-radiological tests, which are rarely performed, exclude cerebral lesions.
Visit the Orphanet disease page for more information.

Research helps us better understand diseases and can lead to advances in diagnosis and treatment. This section provides resources to help you learn about medical research and ways to get involved.

Clinical Research Resources

  • ClinicalTrials.gov lists trials that are related to Idiopathic hypersomnia. Click on the link to go to ClinicalTrials.gov to read descriptions of these studies.

    Please note: Studies listed on the ClinicalTrials.gov website are listed for informational purposes only; being listed does not reflect an endorsement by GARD or the NIH. We strongly recommend that you talk with a trusted healthcare provider before choosing to participate in any clinical study.

Patient Registry

  • A registry supports research by collecting of information about patients that share something in common, such as being diagnosed with Idiopathic hypersomnia. The type of data collected can vary from registry to registry and is based on the goals and purpose of that registry. Some registries collect contact information while others collect more detailed medical information. Learn more about registries.

    Registries for Idiopathic hypersomnia:
    Hypersomnia Foundation’s Registry at CoRDS
     

Support and advocacy groups can help you connect with other patients and families, and they can provide valuable services. Many develop patient-centered information and are the driving force behind research for better treatments and possible cures. They can direct you to research, resources, and services. Many organizations also have experts who serve as medical advisors or provide lists of doctors/clinics. Visit the group’s website or contact them to learn about the services they offer. Inclusion on this list is not an endorsement by GARD.

Organizations Supporting this Disease

These resources provide more information about this condition or associated symptoms. The in-depth resources contain medical and scientific language that may be hard to understand. You may want to review these resources with a medical professional.

Where to Start

  • MedlinePlus was designed by the National Library of Medicine to help you research your health questions, and it provides more information about this topic.
  • The Merck Manuals Online Medical Library provides information on this condition for patients and caregivers. 

In-Depth Information

  • Medscape Reference provides information on this topic. You may need to register to view the medical textbook, but registration is free.
  • MeSH® (Medical Subject Headings) is a terminology tool used by the National Library of Medicine. Click on the link to view information on this topic.
  • The Monarch Initiative brings together data about this condition from humans and other species to help physicians and biomedical researchers. Monarch’s tools are designed to make it easier to compare the signs and symptoms (phenotypes) of different diseases and discover common features. This initiative is a collaboration between several academic institutions across the world and is funded by the National Institutes of Health. Visit the website to explore the biology of this condition.
  • Orphanet is a European reference portal for information on rare diseases and orphan drugs. Access to this database is free of charge.
  • PubMed is a searchable database of medical literature and lists journal articles that discuss Idiopathic hypersomnia. Click on the link to view a sample search on this topic.

Questions sent to GARD may be posted here if the information could be helpful to others. We remove all identifying information when posting a question to protect your privacy. If you do not want your question posted, please let us know.

  1. Chervin R. Idiopathic Hypersomnia. UpToDate. Waltham, MA: UpToDate; April 20, 2018; https://www.uptodate.com/contents/idiopathic-hypersomnia.
  2. Idiopathic Hypersomnia (IH) Standard Characteristics. Hypersomnia Foundation. October 4, 2017; http://www.hypersomniafoundation.org/wp-content/uploads/IH-Standard-Characteristics.pdf.
  3. What Treatments Are Available?. Hypersomnia Foundation. September, 2017; http://www.hypersomniafoundation.org/about-idiopathic-hypersomnia/.
  4. Idiopathic hypersomnia. MedlinePlus. April 12, 2017; https://medlineplus.gov/ency/article/000803.htm.
  5. Sowa NA. Idiopathic Hypersomnia and Hypersomnolence Disorder: A Systematic Review of the Literature. Psychosomatics. March-April 2016; 57(2):152-64. https://www.ncbi.nlm.nih.gov/pubmed/26895727.
  6. Trotti LM. Idiopathic Hypersomnia. Sleep Med Clin. September, 2017; 12(30:331-344. https://www.ncbi.nlm.nih.gov/pubmed/28778232.
  7. Saini P, Rye DB. Hypersomnia: Evaluation, Treatment, and Social and Economic Aspects. Sleep Med Clin. March, 2017; 12(1):47-60. https://www.ncbi.nlm.nih.gov/pubmed/28159097.